Methods of extinguishing fire



ilnite rates 3,033,291 Patented May 8, 1962 Fire extinguishers are known which consist of a tank containing a powder which by means of a compressed gas is expelled upon the seat of fire in the form of a dust. The powder may consist of bicarbonate of soda which when applied upon the fire cuts away the flame. If glowing particles still are left when the application of the powder has ceased it may occur that ignition happens once again.

This disadvantage is eliminated according to the present invention which relates to a method of extinguishing fire by expelling in a dry condition a powdered mixture containing bicarbonate of soda, aluminum sulfate and a proteinaceous material upon the seat of fire. The proteinaceous material may preferably consist of pea flour or casein. A filling agent such as diatomaceous earth or sand may be included in the powdered mixture.

Due to the fact that the powder according to the invention contains aluminum' sulfate in addition to the bicarbonate of soda the advantage is obtained that a development of gas under formation of foam is obtained when the powder gets in contact with moisture or steam present in the seat of fire and said gas contributes to the quenching of the fire and prevent the fire from blazing up again. By adding water after the application of the powder a foam can be produced that contributes to the extinction. This is especially the fact when extinguishing gasoline and oil fires. The proteinaceous material flows on the surface of the seat of fire and swells under formation of a shell which contributes elfectively to the quenching of the fire and prevents the fire from blazing up agaln.

A preferred embodiment of a powder mixture to be used according to the present invention consists of about 500 parts by weight of sodium bicarbonate, about 1500 parts by weight of aluminum sulfate and about 100 parts by weight of proteinaceous material. Another preferred powder mixture may consist of about 400 parts by weight of sodium bicarbonate, 400 parts by weight of aluminum sulfate and 200 parts by weight of pea flour. The proportions of the constituents may vary considerably without substantially changing the extinguishing effect.

In addition to the said constituents the powder mixture may contain casein, borax, dextrine, bone meal, trisodium phosphate or sodium chloride. In order to prevent agglomeration a minor quantity of such an agent as aluminum stearate may be added.

Having now described my invention, what I claim as 1 new and desire to secure by Letters Patent is:

1. A method of extinguishing fire which comprises applying to the seat of the tire in a dry condition a powdered mixture consisting essentially of from 4 to 5 parts of bicarbonate of soda, from 4 to 15 parts of aluminum sulphate and from 1 to 2 parts of a proteinaceous material selected from the group consisting of pea flour and casein.

2. The method of claim 1 in which a filling agent is included in the powdered mixture.

3. The method of claim 1 in which a filling agent selected from the class consisting of diatomaceous earth and sand is included in the powdered mixture.

4. A method of extinguishing fire which comprises expelling upon the seat of fire a dry powdered mixture consisting essentially of about 500 parts by weight of bicarbonate of soda, about 1500 parts by weight of aluminum sulfate and about parts by weight of proteinaceous material.

5. A method of extinguishing fire which comprises expelling upon the seat of fire a dry powdered mixture consisting essentially of about 400 parts by weight of hicarbonate of soda, about 400 parts by weight of aluminum sulfate and about 200 parts by weight of pea flour.

References Qited in the file of this patent UNITED STATES PATENTS 2,324,951 Ratzer July 20, 1943 2,901,428 Schulenburg Aug. 25, 1959 FOREIGN PATENTS 122,638 Australia Mar. 10, 1944 205,046 Australia Feb. 24, 1955 671,204 Great Britain Apr. 30, 1952 

1. A METHOD OF EXTINGUISHING FIRE WHICH COMPRISES APPLYING TO THE SEAT OF THE FIRE INA DRY CONDITION A POWDERED MIXTURE CONSISTING ESSENTIALLY OF FROM 4 TO 5 PARTS OF BICARBONATE OF SODA, FROM 4 TO 15 PARTS OF ALUMINUM SULPHATE AND FROM 1 TO 2 PARTS OF A PROTEINACEOUS MATERIAL SELECTED FROM THE GROUP CONSISTING OF PEAFLOUR AND CASEIN. 